刚学c语言啊哪些地方有错啊

Question

大神来救我
#include
int main()
{
int a,b,c;
for (a=0;a<=100;a=+2)
for (b=0;b<=100;b=++)
{
c=100-a-b;
if (c>=0&&3*a+2*b+c=100)
printf ("大牛有%d头，小牛有%d头，牛宝宝有%d头",a,b,c);
}
return 0;
}

Answer 1

for (a=0;a<=100;a+=2)是这样的 写错了