这里哪里错了？调试的时候发现a小于b的调试结果错了

#include
int main()
{
int a,b;
printf("please input a and b\n");
scanf("%d,%d",&a,&b);
if(a>b)
{
printf("a is the largest number\n");
}
else if(a=b)
{
printf("a and b is the largest number");
}
else if(a{
printf("b is the largest number");
}
return 0;
}

else if(a=b)改为
else if(a==b)