关于#c语言求子串到最后一步运行不出来#的问题，如何解决？

#求子串到最后一步死活运行不出来，寄了，求各位大神看看哪里出了问题，万分感谢！

#include<stdio.h>
#include<string.h>
#define MAXSIZE 100
#include<stdlib.h>
typedef struct{
    char data[MAXSIZE];
    int Length;
}SqString;

int strCompare(SqString *s1,SqString  *s2){
    int i;
    for(i=0;i<s1->Length||i<s2->Length;i++){
    if(s1->data[i]!=s2->data[i]){
        return(s1->data[i]-s2->data[i]);
    }    
    }return (s1->Length-s2->Length);
}
    
void show_strCompare(){
    SqString *s1,*s2;
    int k;
    s1 = (SqString*)malloc(sizeof(SqString));
    s2 = (SqString*)malloc(sizeof(SqString));
    printf("input string s1:");
    gets(s1->data);
    s1->Length=strlen(s1->data);
    printf("input string s2:");
    gets(s2->data);
    s2->Length=strlen(s2->data);
    k=strCompare(s1,s2);
    if(k==0){
        printf("s1=s2\n");
    }else if(k<0){
        printf("s1<s2\n");
    }else{
        printf("s1>s2\n");
    }
    free(s1);
    free(s2);
}

int strSub(SqString *s,int start,int sublen,SqString *sub){
    int i;
    if(start<1||start>s->Length||sublen>s->Length-start+1){
        printf("error!\n");
        
    }
    for(i=0;i<sublen;i++){
        sub->data[i]=s->data[start-1+i];
        sub->Length=sublen; 
    }
    return 0;
}

void show_subString(){
    SqString *s,*sub;
    int i,start,sublen;
    s = (SqString*)malloc(sizeof(SqString));
    sub = (SqString*)malloc(sizeof(SqString));
    printf("input string s:");
    gets(s->data);
    s->Length=strlen(s->data);
    printf("input start:");
    scanf("%d",&start);
    //getchar(); 
    printf("input sublen:");
    scanf("%d",&sublen);
    getchar();
    if(strSub(s,start,sublen,sub)){
    
        printf("substring is:");
        for(i=0;i<sublen;i++){
            printf("%c",sub->data[i]);
        }
    }
    free(s);
    free(sub);
}

int main(){
    show_strCompare();
    show_subString();
    return 0;
}


运行结果：input string s1:jbvkajvb
input string s2:vniewdu
s1<s2
input string s:vhwrvikvbr
input start:1
input sublen:3

--------------------------------
Process exited after 13.4 seconds with return value 0
请按任意键继续. . .





 

你的 strSub() 方法返回0，而C语言中 0 表示 False，非0表示 True。改为 return 1; 这个表达式 if(strSub(s,start,sublen,sub)) 才会为真，才能执行里面的。