c语言fopen错误指针,[求助]文件指针fopen为什么不执行呢?

[求助]文件指针fopen为什么不执行呢?

这是一个完整程序.语法没有错误,输入一个文件老是提示打不开.

单步运行,实际上执行到 if((fp=fopen(filename,"r+"))==NULL)这一步就没有执行.这是为什么呢.

fp指针为NULL.

不解,请指教!

#include

#include

#include

#include

void main(int argc,char *argv[])

{

float **y=NULL,**yy=NULL,**z=NULL;

char filename[20];

int num[3];

void readFile(float ***y,float ***yy,int num[3],char*);

void getZ(float ***y,float ***yy,float ***z,int n,int ynum,int s);

void output(float ***z,float ***yy,int n,int ynum,int s);

if(argc<=1)

{

printf("Please input the name of file:");

scanf("%s",filename) ;

}

else

strcpy(filename,argv[1]);

readFile(&y,&yy,num,filename);

getZ(&y,&yy,&z,num[0],num[2],num[1]);

output(&z,&yy,num[0],num[2],num[1]);

}

void readFile(float ***y,float ***yy,int num[3],char* filename)

{

FILE *fp;

int i,j,k,n,n2=0,prej=0;

float real,imag,m,**p,**Y,**YY;

int search(float **p,int k,int i,int len);

printf("n");

if((fp=fopen(filename,"r+"))==NULL) {

printf("Can't open the filen");

exit(0);

}

fscanf(fp,"%d %d %d",&num[0],&n2,&num[1]);

p=(float**)malloc(n2*sizeof(float*));

for(i=0;i

{

p[i]=(float*)malloc(4*sizeof(float));

fscanf(fp,"%f %f %f %f",&p[i][0],&p[i][1],&p[i][2],&p[i][3]);

}

num[2]=n2;

for(i=0;i

{

if(p[i][0]==0||p[i][1]==0) num[2]--;

for(j=i+1;j

{

if(p[j][0]==p[i][0]&&p[j][1]==p[i][1]||p[j][0]==p[i][1]&&p[j][1]==p[i][0])

{

m=(p[j][2]+p[i][2])*(p[j][2]+p[i][2])+(p[j][3]+p[i][3])*(p[j][3]+p[i][3]);

real=(p[j][2]*p[i][2]-p[j][3]*p[i][3])*(p[j][2]+p[i][2])+(p[j][2]*p[i][3]+p[j][3]*p[i][2])*(p[j][3]+p[i][3]);

imag=(p[j][2]*p[i][3]+p[j][3]*p[i][2])*(p[j][2]+p[i][2])-(p[j][2]*p[i][2]-p[j][3]*p[i][3])*(p[j][3]+p[i][3]);

p[i][2]=real/m; p[i][3]=imag/m;

p[j][0]=p[n2-1][0]; p[j][1]=p[n2-1][1];

p[j][2]=p[n2-1][2]; p[j][3]=p[n2-1][3];

n2--; num[2]--;

free(p[n2]);

}

}

}

fclose(fp);

Y=(float**)malloc(num[0]*sizeof(float*));

YY=(float**)malloc(num[2]*sizeof(float*));

j=0;

m=0;

system("cls");

printf("节点导纳矩阵为:n");

for(i=1;i<=num[0];i++)

{

k=0; /*指针p位置*/

n=0;

Y[i-1]=(float*)malloc(2*sizeof(float));

Y[i-1][0]=0; Y[i-1][1]=0;

while((n2-k)>0)

{

if((n=search(p,k,i,n2))>=0)

{

real=p[n][2]/(p[n][2]*p[n][2]+p[n][3]*p[n][3]);

imag=-p[n][3]/(p[n][2]*p[n][2]+p[n][3]*p[n][3]);

Y[i-1][0]+=real; Y[i-1][1]+=imag;

if((m=p[n][0])>i||(m=p[n][1])>i)

{

YY[j]=(float*)malloc(4*sizeof(float));

YY[j][0]=(float)i-1; YY[j][1]=m-1; YY[j][2]=-real; YY[j][3]=-imag;

j++;

}

}

else break;

k=(n+1);

}

m=0;

printf("Y%d%d=%.4f",i,i,Y[i-1][0]);

if(Y[i-1][1]>=0)printf("+");

printf("%.4fjt",Y[i-1][1]);

for(n=prej;n

{

m+=1;

if((int)m%3==0) printf("n");

printf("Y%.0f%.0f=%.4f",YY[n][0]+1,YY[n][1]+1,YY[n][2]);

if(YY[n][3]>=0)printf("+");

printf("%.4fjt",YY[n][3]);

}

prej=j;

printf("n");

}

printf("n");

num[2]=j;

*y=Y; *yy=YY;

for(i=0;i

free(p);

}

int search(float **pp,int k,int i,int len)

{

int j;

for(j=k;j

{

if(pp[j][0]==i||pp[j][1]==i) return j;

}

return -1;

}

void getZ(float ***Y,float ***YY,float ***Z,int n,int ynum,int s)

{

float **f,sumReal,sumIm;

float **y=*Y;

float **yy=*YY;

float **z=NULL;

int prek=0,i,j,k;

struct u

{

int i;

int j;

float real;

float im;

struct u *next;

struct u *pre;

} *head,*myu,*ui,*uj;

head=NULL;myu=NULL;ui=NULL;uj=NULL;

z=(float **)malloc(sizeof(float*)*n);

for(i=0;i

{

z[i]=(float*)malloc(sizeof(float)*2);

sumReal=0;sumIm=0;myu=head;

while(myu!=NULL&&myu->i

{

if(myu->j==i)

{

sumReal+=(myu->real*myu->real-myu->im*myu->im)*y[myu->i][0]-2*myu->real*myu->im*y[myu->i][1];

sumIm+= (myu->real*myu->real-myu->im*myu->im)*y[myu->i][1]+2*myu->real*myu->im*y[myu->i][0];

}

myu=myu->next;

}

y[i][0]=y[i][0]-sumReal;

y[i][1]=y[i][1]-sumIm;

for(j=i+1;j

{

sumReal=0;sumIm=0;myu=head;ui=NULL;uj=NULL;

while(myu!=NULL&&myu->i

{

if(myu->j==i) ui=myu;

else if(myu->j==j) uj=myu;

if(uj!=NULL&&ui!=NULL&&ui->i==uj->i)

if(y[ui->i][0]!=0||y[ui->i][1]!=0)

{

sumReal+=-(ui->real*uj->real-ui->im*uj->im)*y[ui->i][0]-(ui->im*uj->real+ui->real*uj->im)*y[ui->i][1];

sumIm+= - (ui->real*uj->real-ui->im*uj->im)*y[ui->i][1]+(ui->im*uj->real+ui->real*uj->im)*y[ui->i][0];

}

myu=myu->next;

}

for(k=prek;k

if(yy[k][0]==i&&yy[k][1]==j)

{sumReal+=yy[k][2];sumIm+=yy[k][3];break;}

prek=k;

if(sumReal!=0||sumIm!=0)

{

myu=(struct u*)malloc(sizeof(struct u));

myu->next=NULL;

myu->i=i;myu->j=j;

myu->real=(sumReal*y[i][0]+sumIm*y[i][1])/(y[i][0]*y[i][0]+y[i][1]*y[i][1]);

myu->im=(sumIm*y[i][0]-sumReal*y[i][1])/(y[i][0]*y[i][0]+y[i][1]*y[i][1]);

if(head==NULL)

{

head=myu;

myu->next=NULL;

myu->pre=myu;

}

else

{

head->pre->next=myu;

myu->pre=head->pre;

head->pre=myu;

}

}

}

}

if(head==NULL)

{

z[s][0]=y[s-1][0]/(y[s-1][0]*y[s-1][0]+y[s-1][1]*y[s-1][1]);

z[s-1][1]=-y[s-1][1]/(y[s-1][0]*y[s-1][0]+y[s-1][1]*y[s-1][1]);

}

else

{

f=(float**)malloc((n-s+1)*sizeof(float*));

f[0]=(float *)malloc(2*sizeof(float));

f[0][0]=1;

f[0][1]=0;

ui=head;while(ui!=NULL&&ui->inext;}

for(i=1;i<=n-s;i++)

{

myu=ui;sumReal=0;sumIm=0;

f[i]=(float *)malloc(2*sizeof(float));

while(myu!=NULL&&myu->i

{

if(myu->j==i+s-1)

{

sumReal+=myu->im*f[myu->i-s+1][1]-myu->real*f[myu->i-s+1][0];

sumIm +=-myu->real*f[myu->i-s+1][1]-myu->im*f[myu->i-s+1][0];

}

myu=myu->next;

}

f[i][0]=sumReal;f[i][1]=sumIm;

}

myu=head->pre; head->pre=NULL;

for(i=n-1;i>=0;i--)

{

sumReal=0;sumIm=0;

while(myu!=NULL&&myu->i==i)

{

if(myu->j>=i+1)

{

sumReal+=myu->real*z[myu->j][0]-myu->im*z[myu->j][1];

sumIm +=myu->real*z[myu->j][1]+myu->im*z[myu->j][0];

}

myu=myu->pre;

}

if(i

else

{

z[i][0]=(y[i][0]*f[i-s+1][0]+y[i][1]*f[i-s+1][1])/(y[i][0]*y[i][0]+y[i][1]*y[i][1])-sumReal;

z[i][1]=(y[i][0]*f[i-s+1][1]-y[i][1]*f[i-s+1][0])/(y[i][0]*y[i][0]+y[i][1]*y[i][1])-sumIm;

}

}

}

for(i=0;i

free(y);

while(head!=NULL)

{

ui=head;

head=head->next;

free(ui);

}

*Z=z;

}

void output(float ***Z,float ***YY,int n,int ynum,int s)

{

float **V;

float **z=*Z;

float **yy=*YY;

float I_real=0,I_im=0;

float If[2];

int i=0,j=1;

V=(float **)malloc(sizeof(float*)*(n+1));

V[0]=(float*)malloc(sizeof(float)*2);

V[0][0]=0;V[0][1]=0;

If[0]=z[s-1][0] /(z[s-1][0]*z[s-1][0]+z[s-1][1]*z[s-1][1]);

If[1]=-z[s-1][1] /(z[s-1][0]*z[s-1][0]+z[s-1][1]*z[s-1][1]);

printf("故障点电流If=%.4f",If[0]);

if(If[1]>=0)printf("+");

printf("%.4fjnn各节点电压为:n",If[1]);

for(i=1;i<=n;i++)

{

V[i]=(float*)malloc(sizeof(float)*2);

if(i==s){V[i][0]=V[i][1]=0;continue;}

V[i][0]=1-z[i-1][0]*If[0]+z[i-1][1]*If[1];

V[i][1]= -z[i-1][0]*If[1]-z[i-1][1]*If[0];

printf("V%d=%.4f",i,V[i][0]);

if(V[i][1]>=0)printf("+");

printf("%.4fjt",V[i][1]);

if(j%3==0)printf("n");

j++;

}

for(i=0;i

free(z);

printf("nn各支路电流为:n");

for(i=0;i

{

I_real=(V[(int)yy[i][0]+1][1]-V[(int)yy[i][1]+1][1])*yy[i][3]-(V[(int)yy[i][0]+1][0]-V[(int)yy[i][1]+1][0])*yy[i][2];

I_im=-(V[(int)yy[i][0]+1][1]-V[(int)yy[i][1]+1][1])*yy[i][2]-(V[(int)yy[i][0]+1][0]-V[(int)yy[i][1]+1][0])*yy[i][3];

printf("I%d%d=%.4f",(int)yy[i][0]+1,(int)yy[i][1]+1,I_real);

if(I_im>=0)printf("+");

printf("%.4fjt",I_im);

if((i+1)%3==0)printf("n");

free(yy[i]);

}

free(yy);

for(i=0;i<=n;i++)free(V[i]);

free(V);

}