程序的运行没有问题 但是结果有问题 结果中提示有错误 向各位请教

#include <math.h>

double niandu(double t)/*温度*//*求渣油的粘度*/ { double a,b,z; double c=1500,d=120;/*运动粘度*/ int t1=50,t2=100; a=log(log(c+1.22))-b*log(t1+273); b=log((log(c+1.22))/(log(d+1.22)))/(log((t1+273)/(t2+273))); z=exp(exp(a+b*log(t+273)))-1.22; return z; }

main() {double a=100.0,d; d=niandu(a); printf("%lf",d); }